The Instant Message (IM) service in the mobile communication network may be provided so that users can implement a one-to-one instant message session or an instant message session among multiple users by sending instant messages to each other. In some cases, an instant message system is required to save session content on a user's request, and to enable the user to view the session content or forward the session content to others, i.e. provide the functions of saving, reading, deleting and forwarding the content of the instant message session. The function of saving the session content is a basic function. Other functions can be provided on the basis of the function of saving the session content.
In the prior art, it can be implemented that a server determines whether to save instant messages in a current instant message session on a client's request, however, no solution is specified for the server to save instant messages in the session. Usually, the server has to save all the instant messages in the current instant message session with default.
Therefore, in the function of saving instant messages in the instant message service according to the prior art, the user can not freely select the saving range of the session content as required. Usually, the desired session content is not all the content of the current instant message session, but some specific content of the current session, i.e. some specific instant messages. If all content of the instant message session is saved by the server with default, many of the saved instant messages are not at the user's desire. Accordingly, the storage load in the server is increased, and the processing load of subsequent reading, deleting and sending the session content is also increased.